An image forming apparatus including a main body to process cartridges for the respective colors are removably mountable is known. In the process cartridge, a photosensitive drum and various members for forming toner images on the photosensitive drums are integrated. With this configuration, for example, when the life of the process cartridge comes to an end (for example, the remaining amount of the toner becomes a predetermined amount or less), the process cartridge can be removed from the apparatus main body and a new process cartridge can be mounted to the apparatus main body.
In such an image forming apparatus, the process cartridge is provided with a memory and a cumulative number of printed sheets (number of prints) printed by using the process cartridge is stored in the memory for determining the life of the process cartridge (for example, see JP-A-2001-215862). For example, when the cumulative number of printed sheets (cumulative number of sheets) stored in the memory exceeds a predetermined number, it can be determined that the life of the process cartridge provided with the memory has come to an end.